![]() ![]() The IHFACs are caused by the inter-hemispheric imbalance of the ionospheric solar quiet (Sq) current system at the middle–low latitudes (Van Sabben 1966, 1969, 1970), due to asymmetry of the north–south Sq current vortices that establishes a potential difference between the northern and southern hemispheres (Fukushima, 1979 Tomás et al. Van Sabben ( 1966) first suggested the existence of IHFACs by using the north–south difference of equivalent Sq current. IHFACs flow from the summer hemisphere to the winter hemisphere in the dawn sector and from the winter hemisphere to the summer hemisphere in the noon and dusk sectors (Fukushima, 1994). The Inter-Hemispheric Field-Aligned Current (IHFAC) is one of the major current systems causing changes in the geomagnetic field at low and middle latitudes. The dusk-side IHFAC yearly amplitude tended to be in inverse proportion to solar activity. In contrast, the dusk-side yearly peak-to-peak ∆ D amplitude increased by about 200%. For the dawn and noon sectors, the yearly peak-to-peak ∆ D amplitude in the later solar cycle SC24 decreased by about 35% in comparison with the earlier solar cycle SC23. Solar cycle dependence of IHFACs was exhibited in the dusk sector. The ∆ D variations clearly showed seasonal asymmetry in the dawn and noon sectors, whereas the ∆ D variations in the dusk sector demonstrated seasonal symmetry. The dusk-side IHFACs around March and September–November months disagreed with the Fukushima model. It was confirmed that the dusk-side IHFACs during June and December solstices flow in the same direction of the noontime IHFACs, which was consistent with the IHFAC polarities suggested by the Fukushima model. We investigated the consistency of the dusk-side IHFAC polarity derived from the observations with the polarity expected from Fukushima’s IHFACs model and examined the solar cycle dependence of IHFACs. Recent in situ satellite and ground-based observations have reported that dusk-side current polarity of IHFAC is often opposite to that of the noon IHFAC, being inconsistent with Fukushima's IHFACs model. Sunspot numbers from Belgium SILSO Cenrer.The east–west component of magnetic field variation (∆ D-component) at Davao station (Philippines, geomagnetic latitude: – 2.22˚N) are used to investigate the characteristics of the long-term Inter-Hemispheric Field-Aligned Currents (IHFACs) based on the time-series analysis from August 1998 to July 2020.Daily Flux Density (F10.7) adjusted for 1 A.U, from Canada.Bartels rotation number, the Kp, ap indices obtained from.Impact parameters: ACE, Wind, IMP8, Geotail, Earth via OMNIWeb_Plus Browser.Impact parameters: ISEE3,IMP8, Earth via OMNIWeb_Plus Browser.Merged IMP/ISEE/Wind/ACE/Genesis IMF & Plasma data via OMNIWeb_Plus Browser.Proton fluxes from GOES-11,13,14 (NOAA/NGDC).Proton fluxes from IMPs (Fundamental Technologies, Kansas).data via OMNIWeb_Plus Browser (hourly and high res OMNI) 1-hour LANL plasma data: via FTP(hourly OMNI).LANL plasma data via OMNIWeb_Plus Browser , MIT plasma data via OMNIWeb_Plus Browser , Via OMNIWeb_Plus Browser( for high res OMNI) Via OMNIWeb_Plus Browser (for hourly and high res OMNI) Via OMNIWeb_Plus Browser (for high res and hourly OMNI) and plasma data via OMNIWeb_Plus Browser (Hourly OMNI) Via OMNIWeb_Plus Browser (High res OMNI) ASCII 15-sec data via OMNIWeb_Plus Browser and.Magnetic field data at ACE SCIENCE CENTER,16sec.Further details on our processing steps areĪ comprehensive path to all SPDF-resident heliospheric data is available In creating the high resolution (1m, 5m) and low resolution (1h, 1d,Ģ7d) versions of OMNI. This page shows the data sources and their locations that we used On-line Access to Data Contributing to OMNI ![]()
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